$radio-width:25px;
$radio-height:25px;
$radio-border:#999999;
$radio-checked:#ffffff;
$radio-back-n:#ffffff;
$radio-back-y:orange;

input{
  outline-style: none;
}
input[type="radio"]{
  -webkit-appearance: none;
  vertical-align:middle;
  margin-top:0;
  background:$radio-back-n;
  border:$radio-border solid 1px;
  border-radius: 200px;
  min-height: $radio-height;
  min-width: $radio-width;
}
input[type="radio"]:checked {
  background: $radio-back-y;
  border: none;
}
input[type="radio"]:checked::after{
  content: '';
  margin-top: ($radio-width)/4;
  margin-left: ($radio-width)/4;
  position: absolute;
  background: transparent;
  border: $radio-checked solid 3px;
  border-top: none;
  border-right: none;
  height: ($radio-width)/5;
  width: ($radio-width)/5*2;
  -moz-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg); 
  transform: rotate(-45deg);
}